The present invention relates to a pharmaceutical composition for prophylaxis and treatment of retinal diseases. More specifically, the present invention relates to a pharmaceutical composition and a method for prophylaxis and treatment of retinal diseases which contains a diester of phosphoric acid with ascorbic acid and tocopherol or a pharmacologically acceptable salt of the diester.
A variety of retinal diseases are known. Examples of such retinal disorders include:
(a) vascular disorders and inflammatory or degenerative lesions of the retina resulting from one or more systemic diseases such as diabetes mellitus, hypertension, arteriosclerosis, anemia, leukemia, certain connective tissue diseases (e.g., systemic lupus erythematosus, seeroderma), and some kinds of congenital metabolic abnormalities (e.g., Tay-Sachs' disease, Vogt-Spielmeyer disease,); and PA1 (b) diseases localized in the retina including such kinds of retinal vascular disorders (e.g., retinopathy of prematurity, retinal vein occlusion, retinal artery occlusion, and retinal periphlebitis), retinal inflammation or degeneration resulting from retinal detachment or trauma, retinal degenerative diseases accompanying aging (e.g., senile disciform macular degeneration), and congenital retinal degenerative diseases.
In order to treat a patient for his or her retinal disease, and where it has resulted from one or more systemic diseases, respective systemic causal therapies may be given to the patient, such as administration of hypotensive drugs for hypertension, and hypoglycemic agents for diabetes mellitus, for example. These therapies, however, do not ensure alleviation of relating retinal diseases. In addition, systemic causal therapies sometimes are unsuccessful or unavailable for autoimmune diseases or congenital metabolic abnormalities. Thus, therapies are necessary that are targeted to act on retinal lesions directly. Thus, for example, vasodilators, drugs directed to fortify vascular walls, or thrombolytic agents are applied in the cases of retinal vascular lesions observed in diabetes mellitus, hypertension, retinal vein occlusion, or retinal artery occlusion. However, these drug therapies are not sufficient in their efficacy and, consequently, surgical treatment is often required in practice.
It has been suspected (i) that there might be involved ischemia and hypoxia and resultant peroxidation reactions in the onset and/or advancement of each of the above retinal diseases, and (ii) that excess light might be a risk factor of these diseases, considering the specificity of the retinal function which evokes vision upon the reception of light.
Upon this background, the inventors of the present invention have pursued an investigation in search of a useful drug for treatment of retinal diseases. By studying pharmacological effects of diesters of phosphoric acid, the inventors have found that certain diesters of phosphoric acid with ascorbic acid and tocopherol, are useful as prophylactic and therapeutic agents for a variety of retinal diseases as mentioned above. The present invention have thus been accomplished on the basis of this finding.